The present invention relates to a method and apparatus for using hazardous waste to form non-hazardous aggregate by thermally induced oxidation.
Many industrial processes produce by-products and waste materials that cannot be legally disposed of without some type of containment or treatment. Efforts in the past to dispose of such materials within containment vessels have proved inadequate since lack of attention to the manufacture of such containment vessels or their deterioration results in leakage or spillage of the hazardous waste. Other means of treating hazardous waste include the injection of such materials into wells, however, such materials may not be immobile within the strata into which they are injected and may find their way into underground aquifers.
In addition to the technical problems associated with such disposal techniques, there remains potential liability for anyone using such facilities. Years after the materials are deposited at the disposal site, claims for liability can be generated based on the knowledge that a party has been responsible for placing hazardous material within an approved waste disposal site only to have the disposal site be unsuccessful in preventing dispersion of the waste. Such problems have generated a search for means of using hazardous waste in a manufacturing process to eliminate its hazardous nature to produce a product suitable for sale to and use by the general public. One of the means attempted has been to oxidize the material by passing it through various types of heaters under oxidizing conditions. One such variation of such a process uses a counter-current rotary kiln to induce combustion of the combustible components in the hazardous waste and to aggregate the noncombustible material into a form that could be sold as a commercially valuable and useful product.
Efforts using this particular method have been partially successful in manufacturing a product that will pass the applicable EPA regulations associated with the disposal of waste. These processes, however, have significant shortcomings.
Many of the shortcomings of these previous processes have been eliminated by the use of the apparatus and methods disclosed in U.S. Pat. Nos. 4,922,841 and 4,986,197 to John M. Kent. Those patents disclose apparatus and processes that eliminate the most significant shortcoming associated with the use of hazardous waste in a thermal process, namely the generation of additional noncombustible material that must be disposed of as hazardous waste. The present inventions are improvements of the processes and apparatus disclosed in those patents.
Therefore, it is one object of the present invention to provide an apparatus for using hazardous waste material as a recyclable material in a manufacturing process such that the only products of such an apparatus are non-hazardous and may be sold for use by the general public without concern as to the nature of the input materials that were processed.
It is another object of the invention to convert hazardous solid materials to a non-hazardous, inert aggregate that may be sold without restriction.
It is an additional object of the invention to convert hazardous solid materials to a non-hazardous, inert aggregate in a manner that reduces the amount of potentially hazardous material in the gases within the treatment system.
It is a further object of the invention to provide an apparatus that is not subject to frequent interruptions in its operation for required periodic maintenance or repair.
These and other objects of the invention will be more fully disclosed in the present specification or may be apparent from practice of the invention.